1. Field of the Invention
The present invention relates to a composition releasing bioactive polypeptides and more particularly, to a parenterally administered, slow releasing bioactive pharmaceutical composition which comprises at least one bioactive polypeptide, at least one tocopherol compound, and a release delaying agent.
2. Description of the Prior Art
Most of bioactive polypeptides have short half-life in vivo. In order to maintain the biological activities of the polypeptides during a desirable duration with sufficient effects when administered, it was necessary to administer an excess amount of bioactive polypeptides or to increase the administration frequency. But, the frequent or excessive administration may injure desired goal. Thus, a means for administering the bioactive polypeptides, capable of prolonging the duration of the biological activities for one administration, have been required.
Recently, various studies for satisfying the requirement have been made. Korean Patent Publication No. 89-2631 discloses that a growth hormone is bound to a transition metal such as Zn and the complex is combined with a gelled oil vehicle comprising a mineral oil or plant oil such as peanut oil or sesame oil, a moisturizing agent and a filler. But, its duration was less than desirable. Furthermore, the growth hormone must be complexed with transition metal. For an example, the complex of a growth hormone and Zn is formed by repeating a series of process comprising adding zinc chloride to a growth hormone under a controlled condition to obtain precipitates with preventing to coagulate the precipitates using sterilized deionized-water and centrifuging, and then lyophilizing. The above method is very tedious and time consuming process.
European Patent No. 246,540 suggests a method that insulin is mixed with fatty acid such as palmitic acid, stearic acid or lauric acid and the mixture is formed to tablets, and then the tablet is transplanted into rats. Korean Patent Publication No. 90-6886 discloses that somatotropin of barrier coating type is transplanted into cows and pigs. However, those methods require a surgical operation or special equipments for the transplantation. And also, the solid substance may give the animal bad feeling in comparison with liquid.
In European Patent No. 193,917, the mixture of a growth hormone with watersoluble or dispersable carbohydrate polymer such as dextran, dextrin, starch, glycogen, cellulose and chitonic acid is administered to cows or pigs and tested. But, the duration was only 7 days. The animal often realized the carbohydrate polymer such as dextran as an antigen and sensitively responsed. Therefore, such a mixture is not suitable as pharmaceutical.
European Patent No. 314,421 discloses a composition combined with an oil (major component), a carbohydrate polymer such as dextran and an assistant. But, the method has same problems as European Patent No. 193,917 does.
Korean Patent Laid Open No. 87-1825 discloses that 40 mg of growth hormone bound to zinc mixed with 8 mg of peanut oil. This formulation is administered to pigs and released for 9 days.
As described above, the known compositions containing bioactive polypeptides over-release or over-expense the active components at initial period after the administration and thus the duration is very short. As well, the compositions may show side-effects occurred by any elements of the composition. Optionally, the polypeptide must be bound to metal such as transition metal.
The present inventors have made studies in order to develop a composition suitable to administer bioactive polypeptides to an animal or human, whose durability is excellent in said body. As a result, we found that a composition combining bioactive polypeptides with tocopherol components and an assistant delaying agent shows the best initial-releasing and the durability in vivo.
Such a composition doesn't give troubles such as side-effects. The composition give a synergic effect, instead. Furthermore, without binding polypeptides to metal, the composition has a sufficient durability. Therefore, said composition will be safer.